Not adjustable.
According to the "Fire Alarm Controller" GB4717-2005, the volume of the fire alarm and fault sounds of the fire alarm host is the largest by default and cannot be adjusted at will, let alone lowered. Therefore, the alarm sound volume of the Jade Bird graphic display device cannot be adjusted.
"Fire Alarm Controller" is a patent applied by Wuxi Blue Sky Electronics Co., Ltd. on November 17, 2003. The patent application number is 2003201107925, the announcement number is CN2664092, and the announcement date is December 2004. On the 15th, the inventors were Wang Linxing and Lu Weibin.